Intradermal injector



Aug. 9, 1955 2,714,887

A. VENDITTY INTRADERMAL INJECTOR Filed April 26, 1954 wf H f A/nvezzzfor zzf/zoy vena/159) 9,5%, mm #am jya United States Patent OINTRADERMAL INJECTOR Anthony Venditty, Detroit, Mich., assignor to R. P.Scherer Corporation, Detroit, Mich., a corporation of MichiganApplication April 26, 1954, Serial No. 425,699 3 Claims. (Cl. 12S-173)This invention relates to a hypodermic injector of the needleless typewhich is adapted to inject subcutaneously a very small quantity of uidin the form f a high pressure jet. More particularly, the invention isan adaptation of the hypodermic injector described in copendingapplication Serial No. 94,579, liled May 21, 1949, by R. P. Scherer,which adaptation renders the injector suitable for allergy testing. j

The conventional hypojet injector described in said copendingapplication is adapted to inject the entire contents of an ampule (1cubic centimeter) secured within the nose of the instrument, relativelydeep beneath the skin and into the muscles. For certain uses it isdesirable to inject only a very small quantity of liquid intradermally.The structure of the present` invention is especially suitable foradministering hypodermic injections of the latter type.

It is an object of the present invention to provide a plunger meanswithin the injector for forcing an accurate predetermined portion of thefluid within the containing ampule through the oriiice in the endthereof.

Another object is to provide a plunger means of the type described whichmay be removably secured within the dosage sleeve of a standard hypojetinstrument, above referred to.

These and other objects will become apparent from the followingdescription when read in conjunction with the accompanying drawings, inwhich:

Figure l is an enlarged sectional view through a hypojet injector of thetype shown in the above-mentioned copending application showing the rearhalf thereof, and

Figure 2 is a similar sectional view of the ampulecontaining end of theinjector and a continuation of the right-hand end of Figure 1, bothFigure 1 and Figure 2 showing the parts in latched position.

Figure 3 is a sectional view taken along the line 3-3 of Figure 1.

Figure 4 is a perspective View of the plunger of the invention inassociation with the lower body portions of the injector, with theplunger rod shown in advanced position in broken lines.

Referring generally to the injector Shown in Figures 1 and 2, thenumeral 10 designates a body housing `most of the mechanism of theinjector. A dosage sleeve 12 is screwed onto the threaded forward end ofthe injector and a winding sleeve 14 is rotatable on the rear endthereof. The sleeve 14 has an inturned flange 16 coacting with anannular shoulder 18 on the body 10 to prevent longitudinal movement inone direction relative to the body. A latch housing 20 is screwed intothe rear end of the winding sleeve 14 with a thrust bearing assembly 22interposed between the body and the latch housing.

A release button cap 24 is threaded on the latch housing Ztl and theentire assembly of the winding sleeve 14, `latch housing 20 and cap 24is held in assembled relation by a set screw 26 engaging all three partsand sealed in place as best shown in Figure 3.

The dosage sleeve 12 has threaded on its forward end an ampule holder 3hadapted to receive an ampule 31 having medicament 32 therein and aflexible cup-like follower 33, preferably formed from an Oil resistantrubber such as polychloroprene, or the like. The ampule is provided witha reduced discharge nozzle 34, perforated by a minute discharge orifice35. The ampule holder is covered by a resilient nose 36 which may alsobe made from polychloroprene rubber.

The internal mechanism of the injector includes a cylindrical plunger4t) slidably mounted within the disc or bearing member Si) screwed intothe dosage sleeve 12, said plunger being adapted to propel the follower33 in the ampule 31 thereby discharging or ejecting a fine stream or jetof liquid 32 through the minute orice 35 in the outer end of the ampule.It will be noted that the inner end of the plunger 40 has a shank 41 ofreduced diameter which slides longitudinally within the opening 42 inthe center of the disc or bearing member 50. The bearing member 50 maytake the shape of a cup with a central hollow shaft for the plungerbearing, and externally-threaded side walls that screw inside the dosagesleeve l2. A disc 43 fixed to the end of shank 41 limits the forwardmovement of the plunger 40 while the shoulder 44 limits the rearwardmovement of the plunger. The maximum distance the plunger may bepropelled, therefore, is equal to the difference between the length ofthe shank 41 and the thickness of the disc 50. ln Figure 2, where theplunger 4i) is shown in retracted position, this distance is indicatedby the numeral 47. The distance 47 may be varied in. accordance with thevolume of the liquid desired to be ejected from the ampule by providinga different plunger having a shank 41 of increased or decreased length.

The mechanism for propelling the plunger 40 comprises a nut 60, a screw62 and a plurality of power springs 64. The nut is sleeve-like incharacter and has a disc-like head 66 provided with spring seats for thesprings 64, which springs at their opposite ends seat against apartition 68 of the body lll.

The nut 61B has threads 61 at its left end, as shown in Figure l, whichcooperate with the threads of the screw 62. Nut 60 will not rotate withrespect to the body lil, but is adapted to move longitudinally therein.The screw at its left end, as shown in Figure l, is provided with a head70 providing a latching shoulder 71. The screw head 7d terminates in abifurcated portion which results in a pair of spaced blades 72, the headwith its blades being slidable in a square opening 21 of the latchhousing 20. As shown in Figure 3, the latch housing is provided with across slot 23 in which a latch. 25 is pivotally r, mounted. For thispurpose a pivot pin 27 is press-fitted in the latch and has its endsrotatable in the latch housing. The latch substantially spans the widthof the slot 23 and the space between the blades 72 of the screw, and isof the shape shown in Figure 1, having a latching shoulder 75 and aspring socket 76. A latch spring 77 has one end seated in the socket andits other end seated in an opposing socket 78 of the latch housing fortending to rotate the latch counterclockwise.

Slidably mounted in the release button cap 24 is a release button 80having a crossbar 82 attached thereto and slidable in the slot 23 of thelatch housing 20 and the space between the blades 72 of the screw 62back of the latch 25. When the button 80 is depressed, the latch 25 isrocked against the bias of the spring 77.

A latch roll 83 rotatably mounted in the latch housing prevents thescrew 62, which is biased to the right by springs 63 from moving untilthe latch 25 is released,

3 thus` permitting` the latch roll 83 to rotate out from under theshoulder 71.

The body has five circumferentially spaced posts 90 which extend beyondthe threads 11 and engage the bottom of the disc 50, as shown in Figure4. The posts may be formed by cutting spaced longitudinal slots in theVwall of thebody. Bosses 52 triangular in shape, project from. thebottom` of disc 50 between the posts 9.0' to prevent rotation betweenthe body 10 and the disc 5.0. Thus, when the dosage sleeve 12 is turnedit rotates with respeelt` to both thebody 10,y and the disc 50.

In operation, the ampule 3 1 is placedv withiny the holder'and1securedto the end of the injector., The Winding sleeve 141isrotated, causing the screwv 62: to turn and lift the nut 66 to compressthe springs 64; The. dosage sleeve is then; rotated to bring the ampulefollower 33 into firm contactwith the end of the: plunger 40. TheincreaseV ILOIQUC. IGSStanCe 0f: the sleeve when the plunger meetstheresistance of' the follower indicates when firm contact isA obtained;The; follower should be fitted tightly withinI the ampule for thispurpose.

The plunger is shifted with respect to. disc 50 by this operation sothat the disc43 on the end thereof is spaced from theV disc 5,0 thedistance 47 shown in Figure l. Release is accomplished by depressing thebutton 80 which permits4 the latch roll 83' to rotate out from under theshoulder 71. Thev springs.63 immediately expand causingA thenut 66 to bepropelled within the body 10 and strike the disc'lry a sharpblow. Theplunger 40 and the follower 33 are thus propelled a predeterminedvdistance, that is, the distance between the disc 43` and the disc 50. Inthis way an accurate volume of. medicament is ejected from the orificeof the ampule.

Thev construction described is particularly useful for making allergyinjections in which the volume of medicament. discharged is aboutone-iiftieth of a cubic centimeter. This volume may, of course, beincreased or decreased by lengthening or shortening the length of theshaft 41 ofthe plunger 40; Obviously, other means may be used to limitthe longitudinallmovement of the plunger, the construction shown beingjust` one convenient means for doing so, Any suitable stops'rxedsecurely tothe circumference ofthe plunger will serve for this purpose.

The depth; ofthel injection may be controlled by adjusting the windingsleeve to vary the distance between the nut66 and the disc 43.Increasing the distance will further compress the springs to increasethe impact of the blow and` this in turn increases the pressure atwhichk the liqilid is ejected. Where the liquid volume is small,

the depthy of penetration will necessarily be shallow, usually within`the intradermal range.

layer of skin.

Sincehe. normal volume of an ampule is one cubic centimeter, itisapparent that a large number ofV intradermal injectionsof the allergytype may be adminis,-

tered from a. single ampule. If the injections are not` givensuccessively, as when different medicaments are= It will be noted thatthe plunger and the associated..

disc 50 may be conveniently removed from the instru- Of, course, the,pressure must be; sufficientto penetrate the-,tough outerV ment byscrewing olf the dosage sleeve 12, and screwing the. disc. 5,0 out ofthesleeve. In. this way other plunger assemblies providing longer orshorter plunger travel may be substituted to increase or decrease thevolume of medicament discharged from the ampule.

Various modifications of the structure illustrated will become apparentto those skilled in the art. It is not Amy intention, therefore, tolimit the invention to the particular formA illustrated, other than asnecessitated by, the scopev of the appended claims.

I claim:

l. In a hypodermic injector, an assembly comprising an elongated body,an ampule holder detachably connected to one endfthereof andyadaptedtoehold an oriliced ampule, a plunger slidably mounted within. abearing member threadedly engaged with the inside wall of said body andadapted for engaging and propelling a follower in the ampule todischarge liquid from the ampule through a dischar-ge-or-ilicel therein,said'bearing member being adapted to-- rotate ons-aid threadsI to bringsaid plunger-into firm contact with said follower, meansk for propellingsaid plunger including means` forr` storing the driving energy therein,means for suddenly releasing the energy thus storedtoper-fbrm propulsionofthe plunger andlfollower, and stop means for limiting movementv ofsaid plungerwith respect to said bearing member whereby ameasuredportion of liquid=V is; dischargedk fromV said orifice.

2'; ln a hypodermic injector, an assembly comprising an elongatedV body,an` ampulef holder detachably connectedftoone; end thereof and adaptedto hold an orificed ampule, said body containing al cylindrical plungeradaptedfor-Y engaging and propelling afollower Within the ampule, saidplunger having a shank of reduced diameter andpredeterminedllengthslidably'mounted within a bearing member, said shanlterminating` inshoulders on either sideof said' bearing-- member whereby thelongitudinal movement of said plunger with respect to said bearingmemberJ iselimited', the'said' bearinggmember being threadedlyengaged'w-iththe-insidefwall ofV said body to permit movingfth'eplungerfinto-iirm4 contact withsaid follower, means fon propelling*ysaid plungerincludingmeansv for storinglthedrivingtenergyftherein,andmeans for suddenly releasing the energy thus stored to performpropulsion off'thei plunger andifollower,` whereby a measured portionofliquidri'sdischarged from said oriiice.

3. In a hypoderrnic: injector,- an assemblyV comprisinganelongaterlbodyexternallyv threaded at one end, adosagefsleevefadaptedtoiscrew ontosaid.- threaded portionof` thefbotyyand. carryinganampule'vholder inthe end oppoy site the body adapted to hold an orificedampule, said dosage; sleeve containing1 af plunger: slidably mountedwithirria disc; threadedly; engagedfwithvthe. inside wallof saidlsleeve,,and adapted'for engagingandpropelling a follower in the ampuleto"dischargeliquid therefrom, posts projecting fromthe'; threaded end of.said. body to `engage said disc to prevent rotation of the disc withrespecttof the body, meansarried by saidy bodyfor propellingV saidplunger.V including; means for storinggthe driving energy therein,means, for4 suddenly releasing theY energy thus stored to performpropulsion of the. plunger and follower, and stop means, forlimitingmovement of said plunger withrespectto saidfdiscwhereby ameasured portion of liquid is4 discharged from said orifice.

No references; cited'.

